Book/Report

FZJ-2019-05083

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Excitation functions and isomer ratios of fast neutron induced reactions on zinc, gallium and germanium

Nesaraja, C. D. (Corresponding author)FZJ*

1999
Forschungszentrum Jülich, Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/23106

Report No.: Juel-3701

Abstract: Excitation functions of fast neutron induced reactions are of considerable significance in testing nuclear reaction models. Of special interest are studies of the (n,p),(n,$\alpha$) and (n,2n) reactions on some isotopes of Ge ($^{70, 72, 73, 74}$Ge), Ga ($^{69, 71}$Ga) and Zn ($^{67,68,70}$Zn). Neutrons in the energy range of 6 to 12 MeV were produced via the D-D reaction on D$_{2}$ gas target at the compact cyclotron CV28 at Jülich, Germany. Use was made of the activation technique in combination with HPGe detector $\gamma$- ray spectrometry. In a few cases lowlevel $\beta ^{-}$ counting was also applied and occasionally radiochemical separations were performed. In this work, the following reactions; $^{70}$Ge(n,p)$^{70}$Ga, $^{72}$Ge(n,$\alpha$) $^{69m,g}$Zn, $^{74}$Ge(n,p)$^{74}$gGa, $^{74}$Ge(n,$\alpha$)$^{71m,g}$Zn, $^{69}$Ga(n,p) $^{69m,g}$Zn, $^{71}$Ga(n,p) $^{71m,g}$Zn, $^{71}$Ga(n,2n) $^{70}$Ga, $^{67}$Zn(n,p) $^{67}$Cu and $^{70}$Zn(n,2n)$^{69g}$Zn were investigated in the neutron energy range of 6 to 12 MeV. Prior to this work almost no data existed in this energy range. The measurements provided substantial new information on the investigated process. Measurements were also done on the reactions of $^{73}$Ge(n,p) $^{73}$Ga, $^{68}$Zn(n,$\alpha$) $^{65}$Ni and $^{70}$Zn(n,2n) $^{69m}$Zn where some information existed. Theoretical model calculations using the STAPRE code employing the Hauser Feshbach and the exciton model formalismwere undertaken to describe the cross sections of all these reactions. In most of the cases, the calculated values fit fairly well with the experimental results and it is seen that the calculation is strongly influenced by the level structure of the product. Attempts were made to adjust the input parameters within the limited error to achieve a degree of agreement between the experimental and calculated cross section values. Special emphasis was made on the isomeric cross section ratio namely the isomeric pair $^{69m,g}$Zn and $^{71m,g}$Zn. The isomeric cross section ratios show increasing trends which indicate that the yields of the high spin isomers increase with the increasing incident neutron energies. The ratio of the $^{69m,g}$Zn isomer pair was studied in three different reaction channels (n,$\alpha$), (n,p) and (n,2n) reactions and the (n,p) and (n,$\alpha$) reactions in the $^{71m,g}$Zn isomer ratio. In both cases the population of the high spin isomer is higher in the (n,p) than in the (n,$\alpha$) processes.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000 ; Retrocat)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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